problem with fork & wait

From: T.S. Ravi Shankar (Ravi.Shankar_at_synopsys.COM)
Date: 03/29/04 

Date: Mon, 29 Mar 2004 18:38:48 +0530
To: beginners@perl.org

Hi,

At reaching a certain point in my perl program, I need to run a process
( say XYZ ) using SYSTEM command. The result file that this process
would produce will be result.<process_id>. I will have to wait until
this result file is produced & then proceed extracting certain things
from this file.

I am implementing this as :

foreach $check (@run) {

$pid=fork;
if($pid == 0) {
  exec("XYZ -a $check");
}else{
  $pid1=wait;
}

if ( -e "result.$pid1") {
  ## perform operations on the file result.$pid1##
}

system("rm result.$pid1");

}

This seems to be performing inconsistently. I am seeing this working
properly sometimes & not working properly sometimes. This works on
certain workstations & doesn't work on certain workstations.

Why is this inconsistency ??

I would be satisfied if I am given a clean/consistent/straight forward
implementation methodology for my purpose.

Thanks,
Ravi